Vacuum adiabatic body and refrigerator

ABSTRACT

A vacuum adiabatic body and a refrigerator are provided. The vacuum adiabatic body includes a support that maintains a vacuum space between a first plate and a second plate, and a heat resistance unit comprising at least one radiation resistance sheet that blocks radiation heat transfer in the vacuum space so as to reduce heat transfer between the first plate and the second plate. The support includes two support plates, and the at least one radiation resistance sheet is supported by at least one support protrusion provided on a bar, which couples the two support plates to each other, to maintain an interval between the first plate and the second plate.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation Application of U.S. patentapplication Ser. No. 16/635,758 filed Jan. 31, 2020, which is a U.S.National Stage Application under 35 U.S.C. § 371 of PCT Application No.PCT/KR2018/008691, filed Jul. 31, 2018, which claims priority to KoreanPatent Application No. 10-2017-0097821, filed Aug. 1, 2017, whose entiredisclosures are hereby incorporated by reference.

BACKGROUND Field

A vacuum adiabatic body and a refrigerator are disclosed herein.

Background

A vacuum adiabatic body is a product for suppressing heat transfer byvacuumizing an interior of a body thereof. The vacuum adiabatic body mayreduce heat transfer by convection and conduction, and hence is appliedto heating apparatuses and refrigerating apparatuses. In a typicaladiabatic method applied to a refrigerator, although it is differentlyapplied in refrigeration and freezing, a foam urethane adiabatic wallhaving a thickness of about 30 cm or more is generally provided.However, an internal volume of the refrigerator is therefore reduced.

In order to increase the internal volume of a refrigerator, there is anattempt to apply a vacuum adiabatic body to the refrigerator.

First, Korean Patent No. 10-0343719 (Reference Document 1) of thepresent applicant has been disclosed. According to Reference Document 1,there is disclosed a method in which a vacuum adiabatic panel isprepared and then built in walls of a refrigerator, and an exterior ofthe vacuum adiabatic panel is finished with a separate molding asStyrofoam. According to the method, additional foaming is not required,and adiabatic performance of the refrigerator is improved. However,fabrication cost is increased, and a fabrication method is complicated.As another example, a technique of providing walls using a vacuumadiabatic material and additionally providing adiabatic walls using afoam filling material has been disclosed in Korean Patent PublicationNo. 10-2015-0012712 (Reference Document 2). According to ReferenceDocument 2, fabrication cost is increased, and a fabrication method iscomplicated.

As further another example, there is an attempt to fabricate all wallsof a refrigerator using a vacuum adiabatic body that is a singleproduct. For example, a technique of providing an adiabatic structure ofa refrigerator to be in a vacuum state has been disclosed in U.S. PatentLaid-Open Publication No. US2040226956A1 (Reference Document 3).However, it is difficult to obtain a practical level of an adiabaticeffect by providing a wall of the refrigerator with sufficient vacuum.In detail, there are limitations in that it is difficult to prevent aheat transfer phenomenon at a contact portion between an outer case andan inner case having different temperatures, it is difficult to maintaina stable vacuum state, and it is difficult to prevent deformation of acase due to a negative pressure of the vacuum state. Due to theselimitations, the technology disclosed in Reference Document 3 is limitedto a cryogenic refrigerator, and does not provide a level of technologyapplicable to general households.

The present applicant had filed Patent Application No. 10-2011-0113414(Reference Document 4) in consideration of the above-describedlimitations. Reference Document 4 proposes a refrigerator including avacuum adiabatic body. Particularly, a space maintenance member forinstalling a radiation resistance sheet is built.

According to the document, it is difficult to install the radiationresistance sheet in a supporting unit, particularly, when the radiationresistance sheet is inserted, the space maintenance member formaintaining a space has to be separately inserted. In addition, as amember made of a resin material is used, a weight, cost, and outgassingincrease. Further, as the space maintenance member having apredetermined thickness has to be installed, there is a limitation insecuring an adiabatic thickness of the vacuum adiabatic body.

Embodiments provide a vacuum adiabatic body, which is convenient ininstallation of a radiation resistance sheet in a supporting unit, and arefrigerator. Embodiments also provide a vacuum adiabatic body, in whicha plurality of radiation resistance sheets is conveniently coupled, anda refrigerator. Embodiments provide a vacuum adiabatic body, in which apossibility of damage is reduced, and a refrigerator. Embodiments alsoprovide a vacuum adiabatic body, which is improved in productivity whenbeing assembled, and a refrigerator.

In order to conveniently install a radiation resistance sheet to asupporting unit, the supporting unit may include two support plates, andthe radiation resistance sheet may be supported by a support protrusionprovided on a bar coupling the two support plates to each other and thusbe maintained in position in an interval part between the plate members.In order to conveniently couple a plurality of radiation resistancesheets, at least two kinds of bars may be provided in the supportingunit. In order to prevent the supporting unit from being damaged, an Atype bar provided by coupling a high column provided on the supportplate of one side to a support groove provided in the support plate ofthe other side and a B type bar provided by coupling a multiple highcolumn having a large diameter portion and a small diameter portion,which have diameters different from each other, to an accommodation partprovided on the support plate of the other side to support the smalldiameter portion may be provided.

The details of one or more embodiments are set forth in the accompanyingdrawings and the description below. Other features will be apparent fromthe description and drawings, and from the claims.

According to embodiments, a worker may conveniently assemble thesupporting unit and the radiation resistance sheet together with eachother. According to embodiments, damage of parts may be reduced toimprove product yield. According to embodiments, parts may be shared toreduce stock cost.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view of a refrigerator according to anembodiment;

FIG. 2 is a view schematically showing a vacuum adiabatic body used in amain body and a door of the refrigerator;

FIGS. 3A-3B are views illustrating various embodiments of an internalconfiguration of a vacuum space part;

FIG. 4 is a diagram illustrating results obtained by examining resins;

FIG. 5 illustrates results obtained by performing an experiment onvacuum maintenance performances of resins;

FIGS. 6A-6C are results obtained by analyzing components of gasesdischarged from polyphenylene sulfide (PPS) and low outgassingpolycarbonate (PC);

FIG. 7 illustrates results obtained by measuring maximum deformationtemperatures at which resins are damaged by atmospheric pressure inhigh-temperature exhaustion;

FIGS. 8A-8C are views showing various embodiments of conductiveresistance sheets and peripheral parts thereof;

FIG. 9 is a cross-sectional view of a supporting unit according to anembodiment.

FIG. 10 is a view for explaining an A type bar.

FIG. 11 is a view for explaining a B-11 type bar.

FIG. 12 is a view for explaining a B-12 type bar.

FIG. 13 is a view for explaining a coupling process of the supportingunit.

FIG. 14 is a cross-sectional view of a supporting unit according toanother embodiment.

FIG. 15 is a cross-sectional view of a supporting unit according tofurther another embodiment.

FIG. 16 is a view for explaining a C type bar.

FIG. 17 is a view for explaining a different C type bar.

FIG. 18 illustrates graphs showing changes in adiabatic performance andchanges in gas conductivity with respect to vacuum pressures by applyinga simulation.

FIG. 19 is a graph illustrating results obtained by observing a time anda pressure in a process of exhausting an inside of the vacuum adiabaticbody when a supporting unit is used.

FIG. 20 is a graph illustrating results obtained by comparing a vacuumpressure with gas conductivity.

DETAILED DESCRIPTION

Hereinafter, exemplary embodiments will be described with reference tothe accompanying drawings. The embodiments may, however, be embodied inmany different forms and should not be construed as being limited to theembodiments set forth herein, and a person of ordinary skill in the art,who understands the spirit, may readily implement other embodimentsincluded within the scope of the same concept by adding, changing,deleting, and adding components; rather, it will be understood that theyare also included within the scope.

The drawings shown below may be displayed differently from the actualproduct, or exaggerated or simple or detailed parts may be deleted, butthis is intended to facilitate understanding of the technical idea. Itshould not be construed as limited.

In the following description, the term vacuum pressure means anypressure state lower than atmospheric pressure. In addition, theexpression that a vacuum degree of A is higher than that of B means thata vacuum pressure of A is lower than that of B.

FIG. 1 is a perspective view of a refrigerator according to anembodiment. Referring to FIG. 1 , the refrigerator 1 includes a mainbody 2 provided with a cavity 9 capable of storing storage goods and adoor 3 provided to open/close the main body 2. The door 3 may berotatably or slidably movably disposed to open/close the cavity 9. Thecavity 9 may provide at least one of a refrigerating compartment or afreezing compartment.

Parts constituting a freezing cycle in which cold air is supplied intothe cavity 9. In detail, the parts include a compressor 4 thatcompresses a refrigerant, a condenser 5 that condenses the compressedrefrigerant, an expander 6 that expands the condensed refrigerant, andan evaporator 7 that evaporates the expanded refrigerant to take heat.As a typical structure, a fan may be installed at a position adjacent tothe evaporator 7, and a fluid blown from the fan may pass through theevaporator 7 and then be blown into the cavity 9. A freezing load iscontrolled by adjusting a blowing amount and blowing direction by thefan, adjusting an amount of a circulated refrigerant, or adjusting acompression rate of the compressor, so that it is possible to control arefrigerating space or a freezing space.

FIG. 2 is a view schematically showing a vacuum adiabatic body used inthe main body and the door of the refrigerator. In FIG. 2 , a mainbody-side vacuum adiabatic body is illustrated in a state in which topand side walls are removed, and a door-side vacuum adiabatic body isillustrated in a state in which a portion of a front wall is removed. Inaddition, sections of portions at conductive resistance sheets areschematically illustrated for convenience of understanding.

Referring to FIG. 2 , the vacuum adiabatic body includes a first platemember (first plate) 10 for providing a wall of a low-temperature space,a second plate member (second plate) 20 for providing a wall of ahigh-temperature space, a vacuum space part (vacuum space) 50 defined asan interval part between the first and second plate members 10 and 20.Also, the vacuum adiabatic body includes conductive resistance sheets 60and 63 for preventing heat conduction between the first and second platemembers 10 and 20. A sealing part (sealing) 61 for sealing the first andsecond plate members 10 and 20 is provided such that the vacuum spacepart 50 is in a sealed state. When the vacuum adiabatic body is appliedto a refrigerating or heating cabinet, the first plate member 10 may bereferred to as an inner case, and the second plate member 20 may bereferred to as an outer case. A machine room 8 in which parts providinga freezing cycle are accommodated is placed at a lower rear side of themain body-side vacuum adiabatic body, and an exhaust port 40 for forminga vacuum state by exhausting air in the vacuum space part 50 is providedat any one side of the vacuum adiabatic body. In addition, a pipeline 64passing through the vacuum space part 50 may be further installed so asto install a defrosting water line and electric lines.

The first plate member 10 may define at least one portion of a wall fora first space provided thereto. The second plate member 20 may define atleast one portion of a wall for a second space provided thereto. Thefirst space and the second space may be defined as spaces havingdifferent temperatures. The wall for each space may serve as not only awall directly contacting (facing) the space but also a wall notcontacting (facing) the space. For example, the vacuum adiabatic body ofthe embodiment may also be applied to a product further having aseparate wall contacting (facing) each space.

Factors of heat transfer, which cause loss of the adiabatic effect ofthe vacuum adiabatic body, are heat conduction between the first andsecond plate members 10 and 20, heat radiation between the first andsecond plate members 10 and 20, and gas conduction of the vacuum spacepart 50. Hereinafter, a heat resistance unit provided to reduceadiabatic loss related to the factors of the heat transfer will beprovided. The vacuum adiabatic body and the refrigerator of theembodiment do not exclude that another adiabatic means is furtherprovided to at least one side of the vacuum adiabatic body. Therefore,an adiabatic means using foaming, for example, may be further providedto another side of the vacuum adiabatic body.

FIGS. 3A-32B are views illustrating various embodiments of an internalconfiguration of the vacuum space part. Referring to FIG. 3A, the vacuumspace part 50 may be provided in a third space having a pressuredifferent from that of each of the first and second spaces, for example,a vacuum state, thereby reducing adiabatic loss. The third space may beprovided at a temperature between a temperature of the first space and atemperature of the second space. As the third space is provided as aspace in the vacuum state, the first and second plate members 10 and 20receive a force contracting in a direction in which they approach eachother due to a force corresponding to a pressure difference between thefirst and second spaces. Therefore, the vacuum space part 50 may bedeformed in a direction in which it is reduced. In this case, theadiabatic loss may be caused due to an increase in amount of heatradiation, caused by the contraction of the vacuum space part 50, and anincrease in amount of heat conduction, caused by contact between theplate members 10 and 20.

A supporting unit (support) 30 may be provided to reduce deformation ofthe vacuum space part 50. The supporting unit 30 includes a bar 31. Thebar 31 may extend in a substantially vertical direction with respect tothe plate members to support a distance between the first plate memberand the second plate member. A support plate 35 may be additionallyprovided on at least any one end of the bar 31. The support plate 35 mayconnect at least two or more bars 31 to each other to extend in ahorizontal direction with respect to the first and second plate members10 and 20. The support plate 35 may be provided in a plate shape or maybe provided in a lattice shape so that an area of the support platecontacting the first or second plate member 10 or 20 decreases, therebyreducing heat transfer. The bars 31 and the support plate 35 are fixedto each other at at least one portion, to be inserted together betweenthe first and second plate members 10 and 20. The support plate 35contacts at least one of the first and second plate members 10 and 20,thereby preventing deformation of the first and second plate members 10and 20. In addition, based on an extending direction of the bars 31, atotal sectional area of the support plate 35 is provided to be greaterthan that of the bars 31, so that heat transferred through the bars 31may be diffused through the support plate 35.

A material of the supporting unit 30 will be described hereinafter.

The supporting unit 30 is to have a high compressive strength so as toendure the vacuum pressure. Also, the supporting unit 30 is to have alow outgassing rate and a low water absorption rate so as to maintainthe vacuum state. Further, the supporting unit 30 is to have a lowthermal conductivity so as to reduce heat conduction between the platemembers. Furthermore, the supporting unit 30 is to secure thecompressive strength at a high temperature so as to endure ahigh-temperature exhaust process. Additionally, the supporting unit 30is to have an excellent machinability so as to be subjected to molding.Also, the supporting unit 30 is to have a low cost for molding. A timerequired to perform the exhaust process takes about a few days. Hence,the time is reduced, thereby considerably improving fabrication cost andproductivity. Therefore, the compressive strength is to be secured atthe high temperature because an exhaust speed is increased as atemperature at which the exhaust process is performed becomes higher.The inventor has performed various examinations under theabove-described conditions.

First, ceramic or glass has a low outgassing rate and a low waterabsorption rate, but its machinability is remarkably lowered. Hence, theceramic and glass may not be used as the material of the supporting unit30. Therefore, resin may be considered as the material of the supportingunit 30.

FIG. 4 is a diagram illustrating results obtained by examining resins.Referring to FIG. 4 , the present inventor has examined various resins,and most of the resins cannot be used because their outgassing rates andwater absorption rates are remarkably high. Accordingly, the presentinventor has examined resins that approximately satisfy conditions ofthe outgassing rate and the water absorption rate. As a result,polyethylene resin (PE) is inappropriate to be used due to its highoutgassing rate and its low compressive strength.Polychlorotrifluoroethylene (PCTFE) is not used due to its remarkablyhigh price. Polyether ether ketone (PEEK) is inappropriate to be useddue to its high outgassing rate. Accordingly, it is determined that thata resin selected from the group consisting of polycarbonate (PC), glassfiber PC, low outgassing PC, polyphenylene sulfide (PPS), and liquidcrystal polymer (LCP) may be used as the material of the supportingunit. However, an outgassing rate of the PC is 0.19, which is at a lowlevel. Hence, as the time required to perform baking in which exhaustionis performed by applying heat is increased to a certain level, the PCmay be used as the material of the supporting unit.

The present inventor has found an optimal material by performing variousstudies on resins expected to be used inside the vacuum space part.Hereinafter, results of the performed studies will be described withreference to the accompanying drawings.

FIG. 5 is a view illustrating results obtained by performing anexperiment on vacuum maintenance performances of the resins. Referringto FIG. 5 , there is illustrated a graph showing results obtained byfabricating the supporting unit using the respective resins and thentesting vacuum maintenance performances of the resins. First, asupporting unit fabricated using a selected material was cleaned usingethanol, left at a low pressure for 48 hours, exposed to air for 2.5hours, and then subjected to an exhaust process at 90° C. for about 50hours in a state that the supporting unit was put in the vacuumadiabatic body, thereby measuring a vacuum maintenance performance ofthe supporting unit.

It may be seen that in the case of the LCP, its initial exhaustperformance is best, but its vacuum maintenance performance is bad. Itmay be expected that this is caused by sensitivity of the LCP totemperature. Also, it is expected through characteristics of the graphthat, when a final allowable pressure is 5X10-3 Torr, its vacuumperformance will be maintained for a time of about 0.5 year. Therefore,the LCP is inappropriate as the material of the supporting unit.

It may be seen that, in the case of the glass fiber PC (G/F PC), itsexhaust speed is fast, but its vacuum maintenance performance is low. Itis determined that this will be influenced by an additive. Also, it isexpected through the characteristics of the graph that the glass fiberPC will maintain its vacuum performance will be maintained under thesame condition for a time of about 8.2 years. Therefore, the LCP isinappropriate as the material of the supporting unit.

It is expected that, in the case of the low outgassing PC (L/O PC), itsvacuum maintenance performance is excellent, and its vacuum performancewill be maintained under the same condition for a time of about 34years, as compared with the above-described two materials. However, itmay be seen that the initial exhaust performance of the low outgassingPC is low, and therefore, fabrication efficiency of the low outgassingPC is lowered.

It may be seen that, in the case of the PPS, its vacuum maintenanceperformance is remarkably excellent, and its exhaust performance is alsoexcellent. Therefore, it is considered that, based on the vacuummaintenance performance, the PPS is used as the material of thesupporting unit.

FIGS. 6A-6C illustrate results obtained by analyzing components of gasesdischarged from the PPS and the low outgassing PC, in which thehorizontal axis represents mass numbers of gases and the vertical axisrepresents concentrations of gases. FIG. 6A illustrates a resultobtained by analyzing a gas discharged from the low outgassing PC. InFIG. 6A, it may be seen that H₂ series (I), H₂O series (II),N₂/CO/CO₂/O₂ series (III), and hydrocarbon series (IV) are equallydischarged. FIG. 6B illustrates a result obtained by analyzing a gasdischarged from the PPS. In FIG. 6B, it may be seen that H2 series (I),H₂O series (II), and N₂/CO/CO₂/O₂ series (III) are discharged to a weakextent. FIG. 6C is a result obtained by analyzing a gas discharged fromstainless steel. In FIG. 6C, it may be seen that a similar gas to thePPS is discharged from the stainless steel. Consequently, it may be seenthat the PPS discharges a similar gas to the stainless steel. As theanalyzed result, it may be re-confirmed that the PPS is excellent as thematerial of the supporting unit.

FIG. 7 illustrates results obtained by measuring maximum deformationtemperatures at which resins are damaged by atmospheric pressure inhigh-temperature exhaustion. The bars 31 were provided at a diameter of2 mm at a distance of 30 mm. Referring to FIG. 7 , it may be seen that arupture occurs at 60° C. in the case of the PE, a rupture occurs at 90°C. in the case of the low outgassing PC, and a rupture occurs at 125° C.in the case of the PPS. As the analyzed result, it may be seen that thePPS is most used as the resin used inside of the vacuum space part.However, the low outgassing PC may be used in terms of fabrication cost.

A radiation resistance sheet 32 for reducing heat radiation between thefirst and second plate members 10 and 20 through the vacuum space part50 will be described. The first and second plate members 10 and 20 maybe made of a stainless material capable of preventing corrosion andproviding a sufficient strength. The stainless material has a relativelyhigh emissivity of 0.16, and hence a large amount of radiation heat maybe transferred. In addition, the supporting unit 30 made of the resinhas a lower emissivity than the plate members, and is not entirelyprovided to inner surfaces of the first and second plate members 10 and20. Hence, the supporting unit 30 does not have great influence onradiation heat. Therefore, the radiation resistance sheet 32 may beprovided in a plate shape over a majority of the area of the vacuumspace part 50 so as to concentrate on reduction of radiation heattransferred between the first and second plate members 10 and 20. Aproduct having a low emissivity may be preferably used as the materialof the radiation resistance sheet 32. In an embodiment, an aluminum foilhaving an emissivity of 0.02 may be used as the radiation resistancesheet 32. Also, as the transfer of radiation heat may not besufficiently blocked using one radiation resistance sheet, at least tworadiation resistance sheets 32 may be provided at a certain distance soas not to contact each other. Also, at least one radiation resistancesheet may be provided in a state in which it contacts the inner surfaceof the first or second plate member 10 or 20.

Referring back to FIG. 3B, a distance between the plate members ismaintained by the supporting unit 30, and a porous material 33 may befilled in the vacuum space part 50. The porous material 33 may have ahigher emissivity than the stainless material of the first and secondplate members 10 and 20. However, as the porous material 33 is filled inthe vacuum space part 50, the porous material 33 has a high efficiencyfor resisting the radiation heat transfer. In the present embodiment,the vacuum adiabatic body may be manufactured without the radiationresistance sheet 32.

FIGS. 8A-8C are views showing various embodiments of conductiveresistance sheets and peripheral parts thereof. Structures of theconductive resistance sheets are briefly illustrated in FIG. 2 , butwill be understood in detail with reference to the drawings.

First, a conductive resistance sheet proposed in FIG. 8A may be appliedto the main body-side vacuum adiabatic body. Specifically, the first andsecond plate members 10 and 20 are to be sealed so as to vacuumize theinterior of the vacuum adiabatic body. In this case, as the two platemembers have different temperatures from each other, heat transfer mayoccur between the two plate members. Conductive resistance sheet 60 isprovided to prevent heat conduction between two different kinds of platemembers.

The conductive resistance sheet 60 may be provided with sealing parts 61at which both ends of the conductive resistance sheet 60 are sealed todefining at least one portion of the wall for the third space andmaintain the vacuum state. The conductive resistance sheet 60 may beprovided as a thin foil in unit of micrometer so as to reduce the amountof heat conducted along the wall for the third space. The sealing parts610 may be provided as welding parts. That is, the conductive resistancesheet 60 and the plate members 10 and 20 may be fused to each other. Inorder to cause a fusing action between the conductive resistance sheet60 and the plate members 10 and 20, the conductive resistance sheet 60and the plate members 10 and 20 may be made of the same material, and astainless material may be used as the material. The sealing parts 610are not limited to the welding parts, and may be provided through aprocess, such as cocking. The conductive resistance sheet 60 may beprovided in a curved shape. Thus, a heat conduction distance of theconductive resistance sheet 60 is provided longer than a linear distanceof each plate member, so that the amount of heat conduction may befurther reduced.

A change in temperature occurs along the conductive resistance sheet 60.Therefore, in order to block heat transfer to the exterior of theconductive resistance sheet 60, a shielding part (shield) 62 may beprovided at an exterior of the conductive resistance sheet 60 such thatan adiabatic action occurs. In other words, in the refrigerator, thesecond plate member 20 has a high temperature and the first plate member10 has a low temperature. In addition, heat conduction from hightemperature to low temperature occurs in the conductive resistance sheet60, and hence, the temperature of the conductive resistance sheet 60 issuddenly changed. Therefore, when the conductive resistance sheet 60 isopened to the exterior thereof, heat transfer through the opened placemay seriously occur. In order to reduce heat loss, the shielding part 62is provided at the exterior of the conductive resistance sheet 60. Forexample, when the conductive resistance sheet 60 is exposed to any oneof the low-temperature space and the high-temperature space, theconductive resistance sheet 60 does not serve as a conductive resistoras well as the exposed portion thereof.

The shielding part 62 may be provided as a porous material contacting anouter surface of the conductive resistance sheet 60. The shielding part62 may be provided as an adiabatic structure, e.g., a separate gasket,which is placed at the exterior of the conductive resistance sheet 60.The shielding part 62 may be provided as a portion of the vacuumadiabatic body, which is provided at a position facing a correspondingconductive resistance sheet 60 when the main body-side vacuum adiabaticbody is closed with respect to the door-side vacuum adiabatic body. Inorder to reduce heat loss even when the main body and the door areopened, the shielding part 62 may be provided as a porous material or aseparate adiabatic structure.

A conductive resistance sheet proposed in FIG. 8B may be applied to thedoor-side vacuum adiabatic body. In FIG. 8B, portions different fromthose of FIG. 8A are described, and the same description is applied toportions identical to those of FIG. 8A. A side frame 70 is furtherprovided at an outside of the conductive resistance sheet 60. A part forsealing between the door and the main body, an exhaust port necessaryfor an exhaust process, a getter port for vacuum maintenance, forexample, may be placed on the side frame 70. This is because mounting ofparts is convenient in the main body-side vacuum adiabatic body, butmounting positions of parts are limited in the door-side vacuumadiabatic body.

In the door-side vacuum adiabatic body, it is difficult to place theconductive resistance sheet 60 at a front end portion (front end) of thevacuum space part, i.e., a corner side portion (corner side) of thevacuum space part. This is because, unlike the main body, a corner edgeportion (corner edge) of the door is exposed to the exterior. Morespecifically, if the conductive resistance sheet 60 is placed at thefront end portion of the vacuum space part, the corner edge portion ofthe door is exposed to the exterior, and hence, there is a disadvantagein that a separate adiabatic part should be configured so as toheat-insulate the conductive resistance sheet 60.

A conductive resistance sheet proposed in FIG. 8C may be installed inthe pipeline passing through the vacuum space part. In FIG. 8C, portionsdifferent from those of FIGS. 8A and 8B are described, and the samedescription is applied to portions identical to those of FIGS. 8A and8B. A conductive resistance sheet having the same shape as that of FIG.8A, a wrinkled conductive resistance sheet 63 may be provided at aperipheral portion of the pipeline 64. Accordingly, a heat transfer pathmay be lengthened, and deformation caused by a pressure difference maybe prevented. In addition, a separate shielding part may be provided toimprove adiabatic performance of the conductive resistance sheet.

A heat transfer path between the first and second plate members 10 and20 will be described with reference back to FIG. 8A. Heat passingthrough the vacuum adiabatic body may be divided into surface conductionheat {circle around (4)} conducted along a surface of the vacuumadiabatic body, more specifically, the conductive resistance sheet 60,supporter conduction heat {circle around (2)} conducted along thesupporting unit 30 provided inside of the vacuum adiabatic body, gasconduction heat {circle around (3)} conducted through an internal gas inthe vacuum space part, and radiation transfer heat {circle around (4)}transferred through the vacuum space part.

The transfer heat may be changed depending on various depending onvarious design dimensions. For example, the supporting unit may bechanged such that the first and second plate members 10 and 20 mayendure a vacuum pressure without being deformed, the vacuum pressure maybe changed, a distance between the plate members may be changed, and alength of the conductive resistance sheet may be changed. The transferheat may be changed depending on a difference in temperature between thespaces (the first and second spaces) respectively provided by the platemembers. In the embodiment, a configuration of the vacuum adiabatic bodyhas been found by considering that its total heat transfer amount issmaller than that of a typical adiabatic structure formed by foamingpolyurethane. In a typical refrigerator including the adiabaticstructure formed by foaming the polyurethane, an effective heat transfercoefficient may be proposed as 19.6 mW/mK.

By performing a relative analysis on heat transfer amounts of the vacuumadiabatic body of the embodiment, a heat transfer amount by the gasconduction heat {circle around (3)} may become smallest. For example,the heat transfer amount by the gas conduction heat {circle around (3)}may be controlled to be equal to or smaller than 4% of the total heattransfer amount. A heat transfer amount by solid conduction heat definedas a sum of the surface conduction heat {circle around (1)} and thesupporter conduction heat {circle around (2)} is largest. For example,the heat transfer amount by the solid conduction heat may reach 75% ofthe total heat transfer amount. A heat transfer amount by the radiationtransfer heat {circle around (3)} is smaller than the heat transferamount by the solid conduction heat but larger than the heat transferamount of the gas conduction heat. For example, the heat transfer amountby the radiation transfer heat {circle around (3)} may occupy about 20%of the total heat transfer amount.

According to such a heat transfer distribution, effective heat transfercoefficients (eK: effective K) (W/mK) of the surface conduction heat{circle around (1)}, the supporter conduction heat {circle around (2)},the gas conduction heat {circle around (3)}, and the radiation transferheat {circle around (4)} may have an order of Math Equation 1.

eK_(solid conduction heat)>eK_(radiation transfer heat)eK_(gas conduction heat)  [Equation 1]

Here, the effective heat transfer coefficient (eK) is a value that maybe measured using a shape and temperature differences of a targetproduct. The effective heat transfer coefficient (eK) is a value thatmay be obtained by measuring a total heat transfer amount and atemperature at least one portion at which heat is transferred. Forexample, a calorific value (W) is measured using a heating source thatmay be quantitatively measured in the refrigerator, a temperaturedistribution (K) of the door is measured using heats respectivelytransferred through a main body and an edge of the door of therefrigerator, and a path through which heat is transferred is calculatedas a conversion value (m), thereby evaluating an effective heat transfercoefficient.

The effective heat transfer coefficient (eK) of the entire vacuumadiabatic body is a value given by k=QUAΔT. Here, Q denotes a calorificvalue (W) and may be obtained using a calorific value of a heater. Adenotes a sectional area (m2) of the vacuum adiabatic body, L denotes athickness (m) of the vacuum adiabatic body, and AT denotes a temperaturedifference.

For the surface conduction heat, a conductive calorific value may beobtained through a temperature difference (ΔT) between an entrance andan exit of the conductive resistance sheet 60 or 63, a sectional area(A) of the conductive resistance sheet, a length (L) of the conductiveresistance sheet, and a thermal conductivity (k) of the conductiveresistance sheet (the thermal conductivity of the conductive resistancesheet is a material property of a material and may be obtained inadvance). For the supporter conduction heat, a conductive calorificvalue may be obtained through a temperature difference (ΔT) between anentrance and an exit of the supporting unit 30, a sectional area (A) ofthe supporting unit, a length (L) of the supporting unit, and a thermalconductivity (k) of the supporting unit. Here, the thermal conductivityof the supporting unit is a material property of a material and may beobtained in advance. The sum of the gas conduction heat {circle around(3)}, and the radiation transfer heat {circle around (4)} may beobtained by subtracting the surface conduction heat and the supporterconduction heat from the heat transfer amount of the entire vacuumadiabatic body. A ratio of the gas conduction heat {circle around (3)},and the radiation transfer heat {circle around (4)} may be obtained byevaluating radiation transfer heat when no gas conduction heat exists byremarkably lowering a vacuum degree of the vacuum space part 50.

When a porous material is provided inside the vacuum space part 50,porous material conduction heat {circle around (5)} may be a sum of thesupporter conduction heat {circle around (2)} and the radiation transferheat {circle around (4)}. The porous material conduction heat may bechanged depending on various variables including a kind, and an amount,for example, of the porous material.

According to an embodiment, a temperature difference ΔT1 between ageometric center formed by adjacent bars 31 and a point at which each ofthe bars 31 is located may be provided to be less than 0.5° C. Also, atemperature difference ΔT2 between the geometric center formed by theadjacent bars 31 and an edge portion of the vacuum adiabatic body may beprovided to be less than 0.5° C. In the second plate member 20, atemperature difference between an average temperature of the secondplate and a temperature at a point at which a heat transfer path passingthrough the conductive resistance sheet 60 or 63 meets the second platemay be largest. For example, when the second space is a region hotterthan the first space, the temperature at the point at which the heattransfer path passing through the conductive resistance sheet meets thesecond plate member becomes lowest. Similarly, when the second space isa region colder than the first space, the temperature at the point atwhich the heat transfer path passing through the conductive resistancesheet meets the second plate member becomes highest.

This means that the amount of heat transferred through other pointsexcept the surface conduction heat passing through the conductiveresistance sheet should be controlled, and the entire heat transferamount satisfying the vacuum adiabatic body may be achieved only whenthe surface conduction heat occupies the largest heat transfer amount.To this end, a temperature variation of the conductive resistance sheetmay be controlled to be larger than that of the plate member.

Physical characteristics of the parts constituting the vacuum adiabaticbody will be described. In the vacuum adiabatic body, a force by vacuumpressure is applied to all of the parts. Therefore, a material having astrength (N/m2) of a certain level may be used.

Under such circumferences, the plate members 10 and 20 and the sideframe 70 may be made of a material having a sufficient strength withwhich they are not damaged by even vacuum pressure. For example, whenthe number of bars 31 is decreased so as to limit support conductionheat, deformation of the plate member occurs due to the vacuum pressure,which may negatively influence the external appearance of refrigerator.The radiation resistance sheet 32 may be made of a material that has alow emissivity and may be easily subjected to thin film processing.Also, the radiation resistance sheet 32 is to ensure a sufficientstrength not to be deformed by an external impact. The supporting unit30 is provided with a strength sufficient so as to support the force ofthe vacuum pressure and endure an external impact, and is to havemachinability. The conductive resistance sheet 60 may be made of amaterial that has a thin plate shape and may endure the vacuum pressure.

In an embodiment, the plate member, the side frame, and the conductiveresistance sheet may be made of stainless materials having the samestrength. The radiation resistance sheet may be made of aluminum havinga weaker strength that the stainless materials. The supporting unit maybe made of resin having a weaker strength than the aluminum.

Unlike the strength from the point of view of materials, analysis fromthe point of view of stiffness is required. The stiffness (N/m) is aproperty that would not be easily deformed. Although the same materialis used, its stiffness may be changed depending on its shape. Theconductive resistance sheets 60 or 63 may be made of a material having astrength, but the stiffness of the material is low so as to increaseheat resistance and minimize radiation heat as the conductive resistancesheet is uniformly spread without any roughness when the vacuum pressureis applied. The radiation resistance sheet 32 requires a stiffness of acertain level so as not to contact another part due to deformation.Particularly, an edge portion (edge) of the radiation resistance sheetmay generate conduction heat due to drooping caused by self-load of theradiation resistance sheet. Therefore, a stiffness of a certain level isrequired. The supporting unit 30 requires a stiffness enough to endure acompressive stress from the plate member and an external impact.

In an embodiment, the plate member and the side frame may have thehighest stiffness so as to prevent deformation caused by the vacuumpressure. The supporting unit, particularly, the bar may have the secondhighest stiffness. The radiation resistance sheet may have a stiffnessthat is lower than that of the supporting unit but higher than that ofthe conductive resistance sheet. Lastly, the conductive resistance sheetmay be made of a material that is easily deformed by the vacuum pressureand has the lowest stiffness. Even when the porous material 33 is filledin the vacuum space part 50, the conductive resistance sheet may havethe lowest stiffness, and the plate member and the side frame may havethe highest stiffness.

Hereinafter, a vacuum pressure determined depending on an internal stateof the vacuum adiabatic body is discussed. As already described above, avacuum pressure is to be maintained inside of the vacuum adiabatic bodyso as to reduce heat transfer. The vacuum pressure is maintained as lowas possible so as to reduce the heat transfer.

The vacuum space part may resist heat transfer used only the supportingunit 30. A porous material 33 may be filled within the supporting unitinside of the vacuum space part 50 to resist to heat transfer. Heattransfer to the porous material may be resisted without applying thesupporting unit.

In the above description, as a material suitable for the supportingunit, a resin of PPS has been proposed. These resins often have poorfluidity of the resin during molding, so that a shape of the moldedarticle often fails to properly obtain a desired shape. The bar 31 isprovided on the support plate 35 at intervals of 2 cm to 3 cm, and thebar 31 has a height of 1 cm to 2 cm.

The bar is inserted into the vacuum adiabatic body in a state in whichthe bar is not completely coupled to the support plate due to thematerial and characteristics of the construction described above.Thereafter, when being exhausted, the support plate and the bar arecompletely coupled to each other due to a vacuum pressure. However,there is a fear that damage may occur due to warpage of the bar duringthe coupling process.

In order to fix the height of the radiation resistance sheet 32, aninterval maintenance member is inserted into a gap between the radiationresistance sheets. If the interval maintenance member is provided as aseparate member and inserted into the bar 31, convenience of assemblymay deteriorate.

Hereinafter, a supporting unit for solving the above-describedlimitation will be described.

FIG. 9 is a cross-sectional view of a supporting unit according to anembodiment. Referring to FIG. 9 , the supporting unit may include a pairof support plates 350 in which the bar 31 and the support plate 35 areprovided as one body. That is, the supporting unit may be provided bythe same pair of support plates 350 rotated at a proper angle andcoupled to each other in mirror symmetry. For this, the support plate350 is provided symmetrically in FIG. 9 . Thus, the supporting unit maybe assembled by coupling the pair of support plates 350 to face eachother. Thus, the part may be shared, and stock costs may be reduced. Aheight of the radiation resistance sheet 32 may be supported byinserting the radiation resistance sheet 32 into a center while couplingthe pair of support plates 350 to each other.

In the drawing, A and B indicate different types of bars. FIG. 10 is aview for explaining an A type bar. Referring to FIG. 10 , an A type barmay have a structure in which a high (elongated) column 352 provided onbase 351 of either one (first) of the support plates 350 is coupled to asupport groove 353 provided on the base 351 of the other (second)support plate 350. As a height H1 of the support groove 353 is low evenif the high column 352 is large, the bar 31 is not broken even ifdimensions are slightly wrong, or twisting occurs during fitting.

The radiation resistance sheet is not mounted to or does not contact theA type bar. A hole through which the high column 352 passes withoutcontact may be provided in the radiation resistance sheet 32.

The column includes a circular cross-section and may be manufactured invarious shapes. In this specification, a diameter may mean a maximumdistance connecting an outer circumference of the column.

FIG. 11 is a view for explaining a B-11 type bar. Referring to FIG. 11 ,a B type bar may have a structure in which a multiple high (elongated)column 361 provided on the base 351 of either one (first) of the supportplates 350 is inserted into an accommodation part or portion 365provided on the base 351 of the other (second) support plate 350.

It is seen that the B type bar is provided with B-11 and B-12 type barsprovided in a vertically symmetrical manner. The first reference symbolB refers to a bar of the form constituted by the multiple high columnand the accommodation part. The reference numeral 1 after the seconddash (-) indicates that a length of multiple high column andaccommodation part in the same B type. The first and second referencenumerals 1 and 2 after the third dash (-) refer to the opposite in theup and down (vertical) direction. The same goes for the following.

Thus, FIG. 11 illustrates a B-11 type bar, and FIG. 12 illustrates aB-12 type bar. It is seen that the first and second reference numerals 1and 2 after the third dash (-) are provided opposite to each other whenviewed from a center of the support plate. This means that the samesupport plate is provided in a symmetrical structure.

The B type bar will be described in more detail. First, multiple highcolumn 361 may include a large diameter portion 362 close to the base351 and a small diameter portion 363 far from the base 351. An upper endof the large diameter portion 362 forms a support protrusion 364, andthe radiation resistance sheet 32 may be seated thereon. An inclinedinsertion groove 366 is provided in the accommodation part 365corresponding to the multiple high column 361 so that the smallerdiameter portion 363 may be inserted without being damaged so that thediameter becomes larger toward an inlet thereof.

The accommodation part 365 may correspond to the support groove 353provided in the A type bar and may be referred to as a support groove.In this case, it is understood that a height H2 of the support groove365 provided for the B type bar is higher than a height H1 of thesupport groove 353 provided for the A type bar. In order that theradiation resistance sheet 32 is supported on the support protrusion364, and the insertion of the radiation resistance sheet 32 onto thesmall diameter portion 363 is conveniently performed, it is possible todesign such that a diameter of the large diameter portion 362 islargest, a diameter of the small diameter portion 363 is smaller next(see reference numeral 322 in FIG. 13 ) than the hole in the radiationresistance sheet, and the smallest diameter portion 363 has the smallestdiameter.

Referring again to FIG. 9 , the B type bar may guide a position of theradiation resistance sheet 32. The position of the radiation resistancesheet refers not only to movement of the radiation resistance sheet 32in a two-dimensional planar direction, but also to a height thereof.That is, movement of the radiation resistance sheet 32 in thetwo-dimensional planar direction may be performed by a supporting actionof the hole in the radiation resistance sheet 32 and the multiple highcolumn 361. A height of the radiation resistance sheet 32 may besupported at an interval between the support protrusion 32 and an end ofthe accommodation part 365. Thus, there is no need to provide a spacemaintenance member that is inserted separately to maintain the space ofthe radiation resistance sheets.

As the B-12 type bar and the B-11 type bar are provided together, theheight of the radiation resistance sheet 32 may be supported by only thesupport protrusion 32. However, the height of the support protrusion 32is provided to some extent to support the accurate height of theradiation resistance sheet 32.

In the B type bar, the height H2 of the accommodation part 365 is higherthan the height H1 of the support groove. The accommodation part 365 maynot be provided in the same shape as a mold due to the resin materialhaving low moldability as the height of the accommodation part 365increases. For this, the number of B type bars may be smaller than thenumber of A type bars.

It is recommended that the number of B type bars is minimized to preventdamage to the bar as much as possible. However, it is desirable to havea minimum number of B type bars required for fixing the position of theradiation resistance sheet.

According to the supporting unit shown in FIG. 9 , the holes of theradiation resistance sheet 32 are aligned and inserted into the supportprotrusions 364 of the multiple high columns 361 of one of the supportplates 350 disposed on a bottom side. The plurality of holes and thesupport protrusions 364 may be aligned so that positioning of theradiation resistance sheet is easily performed. Thereafter, the other(first) support plate 350 is aligned with the other (second) supportplate 35 so as to be mirror-symmetrical with respect to the othersupport plate 35, so that coupling of the supporting unit 30 iscompleted. The bar is not damaged even when coupling of the supportingunit 30 is completely performed in the vacuum evacuation process.

FIG. 13 is a view for explaining a coupling process of the supportingunit. Referring to FIG. 13 , it is seen that the multiple high columns361 which are highlighted by a black circle and which provide the B typebar to the support plate 350 are provided symmetrically with respect toan oblique line. In addition, it is seen that the number is smaller thanthat of the A type bar. The radiation resistance sheet 32 is providedwith hole 322 having a small size, which is capable of being caught bythe support protrusion 364 of the multiple high column 361 and hole 321having a large size, which does not contact the high column but passestherethrough.

FIG. 14 is a cross-sectional view of a supporting unit according toanother embodiment. Referring to FIG. 14 , there are two kinds of B typebars. The B type bars includes a B-21 type bar in which large diameterportion 362 of multiple high columns 361 has a height less than a heightof small diameter portion 363 and a B31 type bar in which the largediameter portion 362 of the multiple high columns 361 has a heightgreater than a height of the small diameter portion 363. The B-22 andB-32 type bars differ only in the position of the base 351 on which themultiple high columns 361 are formed. Of course, it is clearlyunderstood from the drawings that the heights of the support protrusion364 and the accommodation part 365 vary corresponding to the types ofthe multiple high columns, that is, B21 and B31 type bars.

In the present embodiment as well, the pair of support plates 350 ismirror-symmetrically provided to each other, so that the supporting unit30 is provided by coupling the same pair of support plates 350 to theformer embodiment. In the case of the present embodiment, two differentradiation resistance sheets 32 may be provided. Thus, it may be clearlyunderstood that radiation resistance is reduced. In the case of thepresent embodiment, the number of A type bars may be reduced to smoothlysupport the radiation resistance sheet 32.

FIG. 15 is a cross-sectional view of a supporting unit according tofurther another embodiment. Referring to FIG. 15 , unlike the embodimentdescribed above and the case in which the radiation resistance sheet 32is supported at the interval between the support protrusion 364 of thecolumn and the end of the accommodation part 365, a feature in which itis supported only at the support protrusion of the support column endmay be characteristically different.

FIG. 16 is a view for explaining a C type bar. Referring to FIG. 16 , ahigh (elongated) column 352 extending from the base 351 of one (first)side is supported through a method in which the support column 371extending from the base 351 of the other (second) side is inserted. Anend of the support column 371 forms a support protrusion 372, and aposition of the radiation resistance sheet 32 may be supported by thesupport protrusion 372 on a two dimensional plane.

The height of the radiation resistance sheet 32 may be held by thesupport protrusion 372 of a same kind but provided upside down. Forexample, the height of the radiation resistance sheet 32 may bemaintained because the radiation resistance sheet 32 is supported indirections opposite to each other by the C-22 type bar and the C-22 typebar. It can be understood with reference to FIG. 15 .

There is a concern that the support column 371 may not be provided witha design shape due to a lack of moldability of the resin material. Adifferent C type bar for solving this limitation is proposed.

FIG. 17 is a view for explaining a different C type bar. Referring toFIG. 17 , a middle column 375 extending from the base 351 of one (first)side is supported by a high support groove 376 extending from the base351 of the other (second) side. An end of the high support groove 376forms a support protrusion 377, and the position of the radiationresistance sheet 32 may be supported by the support protrusion 377 on atwo dimensional plane.

The height of the radiation resistance sheet 32 may be held by thesupport protrusion 377 of the same kind but provided upside down. Forexample, the height of the radiation resistance sheet 32 may bemaintained because the radiation resistance sheet 32 is supported indirections opposite to each other by the C-11 type bar and the C-12 typebar. It can be understood with reference to FIG. 15 .

The C-11 and C-12 type bars show that the middle column 375 is slightlyinserted into the high support groove 376. Therefore, damage to themiddle column 375 and the high support groove 376 due to insertionfailure may be prevented.

The C-21 and C-22 type bars may be suitably used by the worker tomanually fix the position of the pair of support plates. That is, whenthe worker attaches the C-21 type bar and the C-22 type bar between theplate members after assembling, the supporting unit may be completelyassembled in the vacuum evacuation process later.

In the case of the present embodiment, the A-type bar may also beprovided. Also, in the present embodiment, it is possible to support twoor more radiation resistance sheets by making the height of the supportprotrusions 377 and 372 various.

FIG. 18 illustrates graphs showing changes in adiabatic performance andchanges in gas conductivity with respect to vacuum pressures by applyinga simulation. Referring to FIG. 18 , it may be seen that, as the vacuumpressure is decreased, i.e., as the vacuum degree is increased, a heatload in the case of only the main body (Graph 1) or in the case wherethe main body and the door are joined together (Graph 2) is decreased ascompared with that in the case of the typical product formed by foamingpolyurethane, thereby improving adiabatic performance. However, it maybe seen that a degree of improvement of the adiabatic performance isgradually lowered. Also, it may be seen that, as the vacuum pressure isdecreased, gas conductivity (Graph 3) is decreased. However, it may beseen that, although the vacuum pressure is decreased, a ratio at whichthe adiabatic performance and the gas conductivity are improved isgradually lowered. Therefore, the vacuum pressure is decreased as low aspossible. However, it takes a long time to obtain excessive vacuumpressure, and much cost is consumed due to excessive use of a getter. Inthe embodiment, an optimal vacuum pressure is proposed from theabove-described point of view.

FIG. 19 is a graph illustrating results obtained by observing a time anda pressure in a process of exhausting the inside of the vacuum adiabaticbody when a supporting unit is used. Referring to FIG. 19 , in order tocreate the vacuum space part 50 to be in the vacuum state, a gas in thevacuum space part 50 is exhausted by a vacuum pump while evaporating alatent gas remaining in parts of the vacuum space part 50 throughbaking. However, if the vacuum pressure reaches a certain level or more,there exists a point at which the level of the vacuum pressure is notincreased any more (Δt1). After that, the getter is activated bydisconnecting the vacuum space part 50 from the vacuum pump and applyingheat to the vacuum space part 50 (Δt2). If the getter is activated, thepressure in the vacuum space part 50 is decreased for a certain periodof time, but then normalized to maintain a vacuum pressure of a certainlevel. The vacuum pressure that maintains the certain level afteractivation of the getter is approximately 1.8X10-6 Torr.

In the embodiment, a point at which the vacuum pressure is notsubstantially decreased any more even though the gas is exhausted byoperating the vacuum pump is set to a lowest limit of the vacuumpressure used in the vacuum adiabatic body, thereby setting a minimuminternal pressure of the vacuum space part 50 to 1.8X10-6 Torr.

FIG. 20 is a graph obtained by comparing a vacuum pressure with gasconductivity. Referring to FIG. 20 , gas conductivities with respect tovacuum pressures depending on sizes of a gap in the vacuum space part 50are represented as graphs of effective heat transfer coefficients (eK).Effective heat transfer coefficients (eK) were measured when the gap inthe vacuum space part 50 has three sizes of 2.76 mm, 6.5 mm, and 12.5mm. The gap in the vacuum space part 50 is defined as follows. When theradiation resistance sheet 32 exists inside of the vacuum space part 50,the gap is a distance between the radiation resistance sheet 32 and theplate member adjacent thereto. When the radiation resistance sheet 32does not exist inside of the vacuum space part 50, the gap is a distancebetween the first and second plate members.

It was seen that, as the size of the gap is small at a pointcorresponding to a typical effective heat transfer coefficient of 0.0196W/mK, which is provided to an adiabatic material formed by foamingpolyurethane, the vacuum pressure is 2.65X10-1 Torr even when the sizeof the gap is 2.76 mm. It was seen that the point at which reduction inadiabatic effect caused by gas conduction heat is saturated even thoughthe vacuum pressure is decreased is a point at which the vacuum pressureis approximately 4.5X10-3 Torr. The vacuum pressure of 4.5X10-3 Torr maybe defined as the point at which the reduction in adiabatic effectcaused by gas conduction heat is saturated. Also, when the effectiveheat transfer coefficient is 0.1 W/mK, the vacuum pressure is 1.2X10-2Torr.

When the vacuum space part 50 is not provided with the supporting unitbut provided with the porous material, the size of the gap ranges from afew micrometers to a few hundreds of micrometers. In this case, theamount of radiation heat transfer is small due to the porous materialeven when the vacuum pressure is relatively high, i.e., when the vacuumdegree is low. Therefore, an appropriate vacuum pump is used to adjustthe vacuum pressure. The vacuum pressure appropriate to thecorresponding vacuum pump is approximately 2.0X10-4 Torr. Also, thevacuum pressure at the point at which the reduction in adiabatic effectcaused by gas conduction heat is saturated is approximately 4.7X10-2Torr. Also, the pressure where the reduction in adiabatic effect causedby gas conduction heat reaches the typical effective heat transfercoefficient of 0.0196 W/mK is 730 Torr.

When the supporting unit and the porous material are provided togetherin the vacuum space part, a vacuum pressure may be created and used,which is in the middle between the vacuum pressure when only thesupporting unit is used and the vacuum pressure when only the porousmaterial is used.

In the description embodiments, a part for performing the same action ineach embodiment of the vacuum adiabatic body may be applied to anotherembodiment by properly changing the shape or dimension of foregoinganother embodiment. Accordingly, still another embodiment may be easilyproposed. For example, in the detailed description, in the case of avacuum adiabatic body suitable as a door-side vacuum adiabatic body, thevacuum adiabatic body may be applied as a main body-side vacuumadiabatic body by properly changing the shape and configuration of avacuum adiabatic body.

The vacuum adiabatic body proposed in embodiments may be applied torefrigerators. However, the application of the vacuum adiabatic body isnot limited to the refrigerators, and may be applied in variousapparatuses, such as cryogenic refrigerating apparatuses, heatingapparatuses, and ventilation apparatuses.

According to embodiments, the vacuum adiabatic body may be industriallyapplied to various adiabatic apparatuses. The adiabatic effect may beenhanced, so that it is possible to improve energy use efficiency and toincrease the effective volume of an apparatus.

What is claimed is:
 1. A vacuum adiabatic body, comprising: a firstplate: a second plate: a vacuum space provided between the first plateand the second plate; and a support configured to maintain a distancebetween the first plate and second plate; and a radiation resistancesheet to reduce heat radiation between the first plate and second plate,wherein the support includes at least one bar that extends in a firstdirection between the first plate and second plate, and wherein the atleast one bar includes: a first portion that extends in the firstdirection which is different from a second direction in which the firstplate extends; and a second portion provided as a component separatefrom the first portion.
 2. The vacuum adiabatic body of claim 1, whereinthe radiation resistance sheet is disposed between the first portion andthe second portion.
 3. The vacuum adiabatic body of claim 2, wherein theradiation resistance sheet is supported by the at least one bar betweenthe first portion and the second portion.
 4. The vacuum adiabatic bodyof claim 2, wherein the radiation resistance sheet and the first andsecond portions of the at least one bar are placed and assembled in thevacuum space after the radiation resistance sheet is disposed betweenthe first portion and the second portion.
 5. The vacuum adiabatic bodyof claim 2, wherein the radiation resistance sheet and the first andsecond portions of the at least one bar are placed next to or adjacentto the first plate and assembled after the radiation resistance sheet isdisposed between the first portion and the second portion.
 6. The vacuumadiabatic body of claim 2, wherein the radiation resistance sheet andthe first and second portions of the at least one bar are placed betweenthe first plate and the second plate and assembled after the radiationresistance sheet is disposed between the first portion and the secondportion.
 7. The vacuum adiabatic body of claim 1, wherein the radiationresistance sheet is supported by being hung on the at least one bar suchthat the radiation resistance sheet is spaced apart from the firstplate.
 8. The vacuum adiabatic body of claim 1, wherein the at least onebar comprises a support jaw that supports the radiation resistancesheet.
 9. The vacuum adiabatic body of claim 1, wherein the firstportion of the at least one bar includes a column.
 10. The vacuumadiabatic body of claim 1, wherein the second portion of the at leastone bar includes a support groove in which the first portion issupported.
 11. The vacuum adiabatic body of claim 1, wherein the secondportion of the at least one bar includes an accommodation portion inwhich the first portion is supported.
 12. The vacuum adiabatic body ofclaim 1, wherein the second portion of the at least one bar includes asupport column in which the first portion is supported.
 13. A vacuumadiabatic body, comprising: a first plate: a second plate: a vacuumspace provided between the first plate and the second plate; and asupport configured to maintain a distance between the first plate andsecond plate; and a radiation resistance sheet to reduce heat radiationbetween the first plate and second plate, wherein the support includesat least one bar that extends between the first plate and second plate,and wherein the radiation resistance sheet is supported by being hung onthe at least one bar and is spaced apart from the first plate.
 14. Thevacuum adiabatic body of claim 13, wherein the at least one bar includesa column.
 15. The vacuum adiabatic body of claim 13, wherein the atleast one bar includes: a first portion including a first outercircumferential surface having a first diameter; a second portionincluding a second outer circumferential surface having a seconddiameter different from the first diameter; and a third portion thatconnects the first portion and the second portion, wherein the radiantresistance sheet is hung on and supported by the third portion.
 16. Thevacuum adiabatic body of claim 13, wherein the at least one barincludes: a first portion including a first outer circumferentialsurface having a first diameter; and a second portion including a secondouter circumferential surface having a second diameter different fromthe first diameter, wherein the radiant resistance sheet is hung on andsupported by between the first and second portions.
 17. The refrigeratorof claim 13, wherein the at least one bar includes: a first portionincluding a first outer circumferential surface; a second portionincluding a second outer circumferential surface having a shapedifferent from a shape of the first outer circumferential surface; and athird portion that connects the first portion and the second portion,wherein the radiant resistance sheet is hung on and supported by thethird portion.
 18. The vacuum adiabatic body of claim 13, wherein the atleast one bar includes: a first portion including a first outercircumferential surface; and a second portion including a second outercircumferential surface having a shape different from a shape of thefirst outer circumferential surface, wherein the radiant resistancesheet is hung on and supported between the first and second portions.19. A vacuum adiabatic body, comprising: a first plate: a second plate:a vacuum space provided between the first plate and the second plate;and a support configured to maintain a distance between the first plateand second plate; and a radiation resistance sheet to reduce heatradiation between the first plate and second plate, wherein the supportincludes at least one bar including a column portion, the column portiondefining a recess, and wherein the radiation resistance sheet issupported by the column portion.
 20. The vacuum adiabatic body of claim19, wherein the column portion includes: a first surface having an innercircumferential surface defined by the recess; a second surface havingan outer circumferential surface; and a third surface that connects thefirst surface and the second surface, wherein the radiant resistancesheet is hung on and supported by the third surface.